11.3 Gbps, Active Back-Termination,
Differential VCSEL Driver
ADN2530
FEATURES
GENERAL DESCRIPTION
Up to 11.3 Gbps operation
−40°C to +100°C operation
Very low power: ISUPPLY = 65 mA
Typical 26 ps rise/fall times
Full back-termination of output transmission lines
Crosspoint adjust function
PECL-/CML-compatible data inputs
Bias current range: 2 mA to 25 mA
Differential modulation current range: 2.2 mA to 23 mA
Automatic laser shutdown (ALS)
3.3 V operation
Compact 3 mm × 3 mm LFCSP
Voltage-input control for bias and modulation currents
XFP-compliant bias current monitor
The ADN2530 laser diode driver is designed for direct modula-
tion of packaged VCSELs with a differential resistance ranging
from 35 Ω to 140 Ω. The active back-termination technique
provides excellent matching with the output transmission lines
while reducing the power dissipation in the output stage. The
back-termination in the ADN2530 absorbs signal reflections
from the TOSA end of the output transmission lines, enabling
excellent optical eye quality to be achieved even when the
TOSA end of the output transmission lines is significantly
misterminated. The small package provides the optimum
solution for compact modules where laser diodes are packaged
in low pin count optical subassemblies.
The modulation and bias currents are programmable via the
MSET and BSET control pins. By driving these pins with
control voltages, the user has the flexibility to implement
various average power and extinction ratio control schemes,
including closed-loop control and look-up tables. The eye
crosspoint in the output eye diagram is adjustable via the
crosspoint adjust (CPA) control voltage input. The automatic
laser shutdown (ALS) feature allows the user to turn on/off the
bias and modulation currents by driving the ALS pin with the
proper logic levels. The product is available in a space-saving
3 mm × 3 mm LFCSP specified from −40°C to +100°C.
APPLICATIONS
10 Gb Ethernet optical transceivers
10G-BASE-LRM optical transceivers
8× and 10× Fibre Channel optical transceivers
XFP/X2/XENPAK/MSA 300 optical modules
SONET OC-192/SDH STM-64 optical transceivers
FUNCTIONAL BLOCK DIAGRAM
VCC
CPA
ALS
VCC
ADN2530
VCC
IMODP
IMODN
50Ω
50Ω
100Ω
IMOD
VCC
GND
DATAP
DATAN
CROSS
POINT
ADJUST
IBMON
IBIAS
800Ω
800Ω
200Ω
200Ω
200Ω
10Ω
MSET
GND
BSET
Figure 1.
Rev. A
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